A company called AVEXIR have released a 2x4GB RAM kit of DDR3-3100 (PC3-24800)
@ 12-15-15-35. You can pick them up for a mere $2000, a discount of $8000 from the usual price! They don't do too badly in the benchmarks at TechPowerUp and did allow some overclocking above even that insane frequency. There are not too many motherboards which support this speed and these DIMMs get hot so make sure you have thought long and hard before purchasing this kit.

"I've got AVEXIR's latest high-performance Core Series 3100 MHz C12 DIMMs in for testing, and they definitely show what Avexir is capable of. Not for everyone, this blazingly fast kit will probably also make your wallet crumble to dust."